부산대학교 도서관

Background Patterns of genetic variation in a population carry information about the prehistory of the population, and for the human Y chromosome an especially informative phylogenetic tree has previously been constructed from fully-sequenced chromosomes. This revealed contrasting bifurcating and starlike phylogenies for the major lineages associated with the Neolithic expansions in sub-Saharan Africa and Western Europe, respectively. Results We used coalescent simulations to investigate the range of demographic models most likely to produce the phylogenetic structures observed in Africa and Europe, assessing the starting and ending genetic effective population sizes, duration of the expansion, and time when expansion ended. The best-fitting models in Africa and Europe are very different. In Africa, the expansion took about 12 thousand years, ending very recently; it started from approximately 40 men and numbers expanded approximately 50-fold. In Europe, the expansion was much more rapid, taking only a few generations and occurring as soon as the major R1b lineage entered Europe; it started from just one to three men, whose numbers expanded more than a thousandfold. Conclusions Although highly simplified, the demographic model we have used captures key elements of the differences between the male Neolithic expansions in Africa and Europe, and is consistent with archaeological findings. Keywords: Human Y chromosome, Neolithic transition, Population expansion, Demographic modeling, Coalescent simulations, Haplogroup, R1b, E1b1a
Author(s): Michael J Sikora[sup.1] , Vincenza Colonna[sup.1,2] , Yali Xue[sup.1] and Chris Tyler-Smith[sup.1] Background Around 50 to 70 thousand years ago (approximately 60 KYA), modern humans expanded out of Africa, [...]